A device used to prevent passage of flame through a ventilating duct while air is flowing.
NSN 5945-01-420-5891
NSN 5925-00-089-6131
NSN 5990-01-176-2724
NSN 6320-00-194-4252
NSN 6620-00-182-7638
NSN 6145-00-284-1514
NSN 6105-01-029-3764
NSN 5998-01-027-9157
NSN 5835-01-456-3922
NSN 5975-00-876-4299
NSN 5975-01-131-8057
NSN 5905-00-537-2288